how to fix P0420 code in Genesis G70 IG (2017-2023)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical shorts during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) O2 sensors.
  2. Apply penetrating oil to the sensor threads if needed.
  3. Disconnect the electrical connectors from both O2 sensors.
  4. Use the O2 sensor socket to remove the sensors from the exhaust pipe.
  5. Install new sensors by threading them into the exhaust and tightening to the manufacturer’s torque specification (typically around 30-40 ft-lbs).
  6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, torque wrench, gasket scraper, exhaust hanger tool.
• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Remove any exhaust hangers securing the converter using an exhaust hanger tool.
  3. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe using a socket set.
  4. Clean the mounting surfaces of the exhaust system to ensure a proper seal.
  5. Install the new catalytic converter, ensuring it is oriented correctly.
  6. Torque the bolts to the manufacturer's specifications (check service manual for exact values).
  7. Reattach the exhaust hangers.

4. Final Steps

• Reconnect the battery.
• Clear the P0420 code using an OBD-II scanner.
• Start the engine and let it reach operating temperature.